Water-resistant textiles and method of



wa m

United States Patent WATER-RESISTANT TEXTILES AND METHOD OF MAKING THE SAME Leo J. Novak and Joseph T. Tyree, Dayton, Ohio, as-

signors to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation of Ohio No Drawing. Application May 14, 1953,

Serial No. 355,163

24 Claims. (Cl. 117-1395) This invention relates to water-resistant or water-repellent textiles and to a method of treating textiles to impart long-lasting water-resistant or water-repellent characteristics to them.

The treatment of textile materials with emulsions of paraffin, waxes and resins, to render them water-repellent, has been proposed. However, when wax emulsions or the like are applied to textile which are then laundered, they are largely lost due to the action of the soap or detergent used in the laundering operation. Synthetic resins are not entirely satisfactory for use as water-repelling conditioning agents, particularly for textiles which are normally inherently more or less hydrophilic, since the resins which are more or less hydrophobic, do not tend to adhere tenaciously to the base. Usually, a comparatively large amount of the resin is applied and, in order to modify the boardy feel or texture which the heavy resin coating imparts to the cloth or the like, the latter is passed through flexers, after the resin treatment, to break up the resin coating and thereafter the resin occurs on the base in the form of discrete particles. This presents the possibility that hydrophilic fibers of the base will be exposed to moisture. 1

It is among the objects of this invention to overcome the above and other disadvantages characterizing prior attempts to improve the water-resisting properties of textiles.

A particular object is to provide washable textiles which are water-repellent in use and remain dimensional,- ly stable during laundering operations, being substantially unaffected by the customary laundering processes.

Another object is to provide textiles which are waterresistant or water-repellent and have a soft, pleasing hand or feel.

An additional object is to provide a method for simultaneously rendering textile materials water-resistant and applying a finish thereto. 7

Other objects and advantages will be apparent from the ensuing description of the invention.

These objects are accomplished in this invention, which broadly comprises treating textile materials with a dextran or dextran conversion product containing chemically bound radicals derived from fatty acids containing between 8 and 18, preferably between 12 and 18, carbon atoms.

The dextrans are high molecular weight polysaccharides made up of anhydroglucopyranosidic units joined by molecular structural repeating alpha-1,6 linkages and alpha-non1,6 linkages, at least 50% of the linkages being, apparently, alpha-1,6 linkages. The properties of the dextrans, including the molecular structural repeating alpha-1,6 to alpha-non-1,6 linkages ratios, the molecular weight, the water sensitivity and the osmotic pressure in liquids vary.

Dextrans may be obtained in various ways. For example, they may be produced bacterially, for example, by inoculating a nutrient medium containing sucrose, particular nitrogenous compounds and certain inorganic salts,

2,734,005 Patented Feb. 7, 1956 ice with an appropriate microorganism, such as those of the Leuconostoc mesenteroides and L. dextranicum types and incubating the culture at the temperature most favorable to the growth of the particular microorganism.

In one method of obtaining a dextran to be esterified to produce the textile treating and conditioning agents of the invention, there is first prepared an aqueous nutrient medium which may have the following composition:

Percent by weight Sucrose 20.0 Corn steep liquor 2.0 Monobasic potassium phosphate 0.5 Manganous sulfate 0.002 Sodium chloride 0.50 Water Balance proximately -85% of water and is a thick turbid liquid.

Upon completion of the fermentation, which process renders the material somewhat acid, that is, to a pH of 3.55.5 (average 4.2), calcium chloride is added to the ferment to bring the pH thereof to about 7.0 to 8.0 This aids in the precipitation of phosphates. Thereafter, acetone or alcohol, which may be a Water-miscible aliphatic, such as methyl, ethyl or isopropyl, is added in sufficient quantity to precipitate the dextran and this brings down, with the dextran, occluded and adsorbed bacteria, and nitrogenous and inorganic elements. Tooccasion complete precipitation of the dextran it may be desirable to allow the mix to stand for a relatively long period, such as about 6 hours. The precipitated dextran may be dried in any suitable manner, for example by drum drying. Thereafter, it may be reduced to particulate condition.

A purer dextran may be obtained by adding an aliphatic alcohol to the fermented culture at a pH between about 2.5 and 4.5. The precipitate thus obtained may be further purified by again precipitating it with the alcohol. Several precipitations may be performed.

The dextran thus produced is a so-called native dextran having a high molecular weight and being, in the particular case, soluble in water at ordinary temperatures.

The higher fatty acid radicals may be introduced into the molecule of high molecular weight dextrans such as the native product obtained as described above or an equivalent dextran, or dextrans of high molecular weight may be hydrolyzed to products of lower molecular weight prior to introduction of the fatty acid radicals. The hydrolysis may be effected in any suitable way, as by means of acid or enzymatically. For example, the dextran which is esterified may be obtained by hydrolyzing the initially water-soluble dextran obtained as described above, or a similar high molecular weight dextran, to a product having a molecular weight or average molecular weight in the range between 20,000 and 100,000, fractionating the hydrolysis product, if necessary to obtain a fraction of preselected uniform or more nearly uniform molecular weight, and purifying the same by known methods for the removal of pyrogens and coloring materials. The dextran may be a so-called clinica dextran such as may be used as a blood plasma extender. In general, the dextran'may have a molecular weight between 5,000 and 50 l0 as determined by light scattering measurements. The preferred dextran ester, particularly for rendering the textile water-repellent, is a high y substituted palmitate or stearate derived from a native (nnhydrolyzed) dextran.

The dextran may be obtained by inoculating the culture medium with microorganisms other than that mentioned above. Thus it may be a water-soluble dextran obtained by the use of the microorganisms bearing the following NRRL classifications: Leuconostoc mesenteroides 13-119, B-1146, B-1190, or a water-insoluble or substantially Water-insoluble .dextran obtained by the use of Leuconostoc mesenteroides B-742, 13-1191, B-1196, B4208, B-1216, B-1120, B-1144, B523, Streptobacterium dextranicum 13-1254 and Betabacterium vermiforme B4139.

The dextran is not limited to one prepared under any particular set of conditions, including the microorganism used. It may be produced enzymatically, in the substantial absence of bacteria, by cultivating an appropriate microorganism, for example, Leuconostoc mesenteroides 13-512 to obtain a dextran-producing enzyme, separating the enzyme. from the medium in which it is produced, and introducing the enzyme into a medium in which dextran is produced by the action of the enzyme. Also, the dextran may be obtained by bacterial conversion of 1,4 linkages of dextrin to 1,6 linkages of dextran. The dextran may be insoluble in water under-ordinary conditions but soluble in aqueous alkali solution.

The higher fatty acid radical-s may be introduced into the dextran molecule by any appropriate method, to pro duce the dextran fatty acid esters to be incorporated into the regenerated cellulose or similar fibers. The esters may be prepared by the methods described in our pending application, Serial No. 351,743, filed April 28, 1953.

Thus, the dextran, in the form of a free-flowing, white powder, may be reacted with an esterifying derivative of the higher fatty acid, and preferably a halide such as the chloride thereof, in the presence of an acid acceptor or binding agent such as an organic base, as for instance a heterocyclic tertiary amine of the type of quinoline, pyridine, n-methyl morpholine, etc. and in the presence of a substance in which the reaction product is at least partially solvated, that is dissolved or swollen, as it is formed during the reaction, which results in the reaction mass being maintained in a highly swollen or dissolved state and thus insures substantially uniform, homogeneous reaction between the dextran and the esterifying agent. Substanceswhichdissolveor swell the ester as it is folmed are, for example, xylene, toluene, ,dioxane, etc. In general, the reactionmay be carried out at temperatures between 100 C. and 155 C. for time periods varying inversely with the temperature between a half hour and three hours. Theestermay be recovered from the crude reaction mixture by washing the latter with water to remove the hydrochloride of the organic base, removing the aqueous layer, adding a solvent for the ester to the residual mass, precipitating the solution into a non-solvent for the ester, such as a lower aliphatic alcohol, and filtering to obtain the ester.

Or the introduction of the higher fatty acid radicals into the dextran molecule may be effected by reacting the dextran with the selected acid in the presence of an impeller which may be the anhydride of a monohalogenated monobasic organic acid, e. g., monochloro acetic anhydride, and an esterification catalyst such as magnesium perchlorate at temperatures at which the reaction mixture remains in the liquid state, in general in the range between 50 C. and 100 C. and for a time varying inversely with the temperature between one-half hour and two hours. The ester may be isolated from the crude reaction mass by cooling the mass, dissolving it in a solvent therefor, precipitating it into a non-solvent for the ester, and filtering the ester.

The higher fatty acids which may be used :as esterification agent, in the free acid'form or inthe formof their chlorides, are those saturated containing from 8 to 18 carbon atoms and including caprylic, pelargonic, palmitic, margaric, and stearic acids, and the corresponding chlorides. Two or more of the substantially pure acids, or chlorides thereof, may be used, resulting in the production of mixed dextran esters. 'Or commercial acids, which comprise mixtures, may be used. For example, commercial or technical grade stearic acid, which comprises a mixture of stearic and palmitric acids, yields dextran stearate-palmitate.

The D. S. (degree of substitution or ratio of fatty acid radicals to anhydroglucopyranosidic units of the dextran) may vary, and maybe from less than 1.0, say up-to about 20.0 or even higher, acid radicals per anhydroglucopyranosidic unit to about the possible maximum of 3.0 of the fatty acid radicals per anhydroglucopyranosidic unit. Such esters may be obtained by using the fatty acid or its chloridein amounts varying between less than 1.0, y 8 0K110 parts-thereof byweight per part ofdextran. Unlike theinherently hydrophilic dextrans from which they are derived, the fatty acid esters are resistant to moisture to an extent which depends on the D. 8., the higher theproportion of fatty acid radicals per anhydroglucopyranosidic unit, the greater the water resistance. When the D. S. approaches the possible maximum of 3.0 fatty acid radicals per .anhydroglucopyranosidic unit, the esters are definitely hydrophobicand Water-repelling, and may be usedto. impart long-lasting water-repellency to the textile.

The partial, esters, i. e. those containing available free hydroxylgroups and less than, say, 2.0 fattyacid radicals per anhydroglucopyranosidic unit of the, dextran, e. g. those in which the ratio of anhydroglucopyranosidic units to fatty acid radicals is between 112.0 and 1:20.0 or higher, are ,both hydrophilic and hydrophobic. Such esters may have balanced.hydrophilic-hydrophobic properties, or they may be predominantly hydrophilic or predominantly hydrophobic. The partial esters impart increased water-resistance to textiles without rendering the same definitely hydrophobic or water-repellentand may be usedto modify the water pick-up and retention capacity of fibers made of such materials as regenerated cellulose so thatthe fibers, or yarns, fabrics and the'like comprising them, pick up and retain a controlled amount of moisture without inducing swelling-of the fibers. For example, dextran higher fatty acid esters within the scope of this invention and containing an average of 1.0 or less than 1.0 higher fatty acid radical per anhydroglucopyranosidic unit have an aflinity for cellulose and tend to prevent pickrup of moisture in sufiicient amount to result in pushing apart of the cellulose walls formed by adjoining cellulose chains and the lateral swelling of the fibers which takes place when water is held in the interstitial gaps in cellulose.

The esters, and more particularly those derived from the saturated fatty acids of the higher carbon content, i. ,e. the longer chain acids containing from 12 to 18 carbons, .have a wax-like consistency and, in addition tov modifying the water resistance of-the textile, also impart to it a soft smooth hand or feel similar to that of a soft finish.

In carrying out the invention, the textile is treated-with a liquid medium comprising the higher fatty acid ester, at room or slightly elevated temperatures, andthe imptegnated textile is then dried. The esters may be used in varying amounts, depending on the purpose and the fibers of which the textile is comprised, as well as the form of the textile. Proportions of the ester between 1% and'5% byweight of the treating medium have been found satisfactory in most cases. The esters may be applied from aqueous dispersions or emulsions or from solutions thereof in non-polar solvents such as the halogenatedhydrocarbons, e. g., eliloroform and carbontetrachloride, or thecommon aromatic-hydrocarbons of the type ofbenzene, tolueneand the-xylenes.

After the treated textile is dried, it is found to comprise aprotective film or coating which is intimately associated with the base and firmly adherent to it. The film is not removed when the textile is repeatedly washed with soap and water, especially when the more highly substituted esters are used, and serves to maintain the textile dimensionally stable during repeated laundering.

These esters, being soluble in hydrocarbon solvents of the type conventionally employed in dry-cleaning processes, may be applied to garments and the like in the course of dry-cleaning the same, and at the-stage of the drycleaning procedure immediately preceding drying of the textile.

The textile may take any form, such as fibers, yarns, fabrics and articles of clothing. Discontinuous fibers may be treated in the form of loose masses, preparatory to spinning them into a yarn, or continuous filaments may be treated in the form of a tow or filamentary bundle; yarns may be treated in the form of skeins, hanks, wound packages which may or may not include a core or support for the yarn, such as bobbins, spools, or unsupported cakes. The treating media comprising the dextran ester may be applied to the textile in any suitable way, as by dipping, spraying, brushing, etc. Loose masses of discontinuous fibers may be placed on a reticulated conveyor moving continuously through and below the level of a bath containing the ester, filaments, filamentary bundles and yarns may be treated in the form of running lengths or, when in wound package form, by pumping the solution through the package from the inside to the outside thereof, or vice versa, and in this latter embodiment, propulsion of the treating medium through the package and uniform distribution of the ester on the layers of yarn making up the package may be facilitated by carrying out the impregnation in a field of high frequency sound waves.

The textile may comprise fibers, filaments or yarns of cotton, wool, regenerated cellulose, cellulose esters such as cellulose acetate, casein, linen, jute, hemp, silk, synthetic fiber-forming resins such as the polyamides of the nylon and Perlon type, etc.

The following specific examples will illustrate specific embodiments of the invention. These examples are merely llustrative and are not to be construed as limiting the underlying principles of the invention.

Example I Khaki-dyed poplin is immersed in a carbon tetrachloride solution of 5% of dextran palmitate containing an average of 2.9 palmitoyl radicals per anhydroglucopyranosidic unit of the dextran for about minutes. The fabric is removed from the treating medium and dried. The dried fabric, after four launderings with soap and water, exhibits excellent Water-repelling characteristics.

Example 11 A fabric woven from regenerated cellulose yarns is treated for about 15 minutes in a 5% chloroform solution of dextran stearate containing an average of 2.9 stearoyl groups per.anhydroglucopyranosidic unit of the dextran. The fabric is removed from the treating solution and dried. The dried fabric comprises a protective film of the ester and exhibits excellent water-repelling characteristics after four launderings with soap and water.

As has been stated, the foregoing examples illustrate specific embodiments of the invention, but it is to be understood that the invention is not limited thereto. Thus, the proportion of the ester in the treating medium and the treating time may be adjusted to insure that the textile picks up an amount of ester such that it is adequately coated or impregnated therewith. The proportion of ester and the treating time may be correlated with the character of the textile, increased amounts of the ester and longer treating times usually being preferred when the textile treated is a heavy fabric such as a Wool blanket, for example. The ester may be used in amounts up to 15% of the treating medium or even higher; treating time of one hour or more may be desirable to insure thorough impregnation of thick articles.

Although the invention has been exemplified in connection with rendering textiles Water-repellent by the use of highly substituted fatty acid esters of dextran, the lowly substituted esters may be used for modifying moisture pick-up of the textile to a controlled extent, as stated hereinabove. Also, dextran conversion products containing the chemically bound radicals derived from the acids of 818 carbon atoms and, in addition, other .substituent groups may be used. The dextran conversion products may be dextran lower fatty acid esters, i. e., esters of fatty acids of from 15 carbon atoms, such as dextran acetate, dextran propionate, dextran butyrate, dextran acetate-propionate and dextran acetate-butyrate; alkylated dextrans in which the alkyl radical contains from 1 to 5 carbon atoms, such as methyl and ethyl dextran; aralkylated dextrans in which the aralkyl radical contains a total of 7 to 10 carbon atoms; and carboxyalkyl dextrans in which the alkyl portion of the carboxyalkyl group contains from 1 to 5 carbon atoms, such as carboxymethyl dextran. These higher fatty acid esters of the dextran conversion products may contain an average of from less than 1.0 to not more than 1.5 of the lower acyl, alkyl, aralkyl or carboxyalkyl groups and from less than 1.0 up to about 1.5 of the higher acyl radicals, per anhydroglucopyranosidic unit of the dextran. The proportion of higher acyl radicals may be higher than 1.5 when the conversion product contains a low proportion of the lower acyl or similar groups. Stated another way, the ratio of lower acyl, alkyl, aralkyl or carboxyalkyl groups to anhydroglucopyranosidic units may be from less than 1:1 to 15:1, and the ratio of anhydroglucopyranosidic units to radicals derived from the fatty acids containing 8 to 18 carbon atoms may be from less than 1:1 to 1:29, preferably to 1:25.

The treating medium comprising the dextran or dextran conversion product comprising the radicals derived from fatty acids of from 8 to 18 carbon atoms, and more particularly those containing radicals derived from the acids of from 12 to 18 carbon atoms and having waxlike properties, may be modified by the inclusion of other adjuvants or agents which contribute to the effects of the ester, such as amine soaps, polyvalent metal salts of organic acids, silica, etc.

It will be understood that while there have been described herein certain specific embodiments of this invention, it is not intended thereby to have it limited to or circumscribed by the specific details given, in view of the fact that this invention is susceptible of various modifications and changes which come within the spirit and scope of this disclosure and of the appended claims.

We claim:

1. A method for rendering a textile material waterrepellent which comprises treating said material with a solution of dextran palmitate containing, per anhydroglucopyranosidic unit, from 2.5 to about 3.0 chemically bound palmitoyl radicals, in a halogenated hydrocarbon, and then drying the textile to leave thereon an adherent protective coating consisting essentially of the dextran ester.

2. A method for rendering a textile material waterrepellent which comprises treating said material with a chloroform solution of dextran palmitate containing, per

anhydroglucopyranosidic unit, an average of about 2.9 palmitoyl radicals, and then drying the textile to leave thereon an adherent protective coating consisting essentially of the dextran ester.

3. A method for rendering a textile material waterrepellent which comprises treating said material with a chloroform solution of dextran stearate containing, per anhydroglucopyranosidic unit, an average of about 2.9

stearoyl radicals, and then drying the textile to leave thereonan adherent, protective coating consisting essentially of the dextran ester.

-4. A'fibrous textile article having adhered thereto a protective water-resistant coating consisting essentially of an ester of dextran, containing initially at least some free hydroxyl groups, with a saturated fatty acid containing from 8 to 18 carbon atoms.

5. A fibrous textile article having adhered thereto a protective Water-resistant coatingconsisting essentially of an ester of dextran with a saturated fatty acid containing from 8 to-18 carbon atoms.

6. A fibrous textile article having adhered thereto a protective Water-resistant coating consisting essentiallyof an ester of dextran with a saturated fatty acid containing from 12 to 18 carbon atoms.

7. A fibrous textile article having adhered thereto a protective, water-resistant coating consisting essentially of dextran palmitate.

8. A fibrous textile article having adhered thereto a protective Water-resistant coating consisting essentially of dextran stcarate.

9. A fibrous textile article having adhered thereto a Water-repellent coating consisting essentially of an ester of dextran with a saturated fatty acid containing 8 to 18 carbon atoms, said ester containing an average of from 2.5 to 3.0 radicals derived from the fatty acid per anhydroglucopyranocidic unit of the dextran.

10. A fibrous textile article having adhered thereto a water-repellent coating consisting essentially of an ester of dextran with a saturated fatty acid containing 12 to 18 carbon atoms, said ester containing an average of from 2.5 to 3.0 radicals derived from the fatty acid per anhydroglucopyranosidic unitof the dextran.

11. A fibrous textile article having adhered thereto a Water-repellent coating consisting essentially of an ester of dextran with palmitic acid, said ester containing an average of from 2.5 to 3.0 .palrnitoyl radicals per anhydroglucopyranosidic unit of the dextran.

12. A fibrous textile article having adhered thereto a water-repellent coating consisting essentially of an ester of dextran with stearic acid, said ester containing an averagent from 2.5 to 3.0 stearoyl radicals per anhydroglucopyranosidic unit of the dextran.

13. A fibrous textile article having adhered thereto a water-repellent coating consisting essentially of an ester of dextran with palmitic acid, said ester containing an average of 2.9 palmitoyl radicals per anhydroglucopyranosidic unit of the dextran.

14. A fibrous textile article having adhered thereto a Water-repellent coating consisting essentially of an ester of dextran with stearic acid, said ester containing'an average of 2.9 stearoyl radicals per anhydroglucopyranosidic unit of the dextran.

15. A fibrous textile article having adhered thereto a water-repellent coating consisting essentially of a mixed ester of dextran with a lower saturated fatty acid containing from 1 to 5 carbon atoms and a higher saturated fatty acid containing from 8 to 18 carbon atoms, said ester containing, per anhydroglucopyranosidic unit of the dextran, an average of less than 1.0 to 1.5 radicals derived from .the lower fatty acid and an average of less than 1.0 to 2.9 radicals derived from the higher fatty acid.

16. A fibrous textile article having adhered thereto a water-repellent coating consisting essentially of an ester of an alkyl ether of dextran in which the alkyl radicals contain from 1 to 5' carbon atoms with .a .saturatediatty acid containing from :8 to .18 carbon atoms, said ester containing, .per :anhydroglucopyranosidic unit of .the .dextran, an average of less than 1.0 to 1.5 ofthealkylradicals and an average ofless than 1.0 to 2.9 radicals. derived from the. fatty acid.

17. A fibrous textile article having adhered thereto a Water-repellent coating consisting essentially of anester of an .aralkylated-dextran in which thearalkyl radicals contain from 7 to 1-0 carbon atoms with a saturated fatty acid containing from 8 to 18 carbon atoms, said 'aralkylated ester containing, :per .anhydroglucopyranosidic .unit of the dextran, an average of less than 1.0 to 1.5 aralkyl radicals and an average of. less than 1.0 to 2.9 radicals derived from the .fattyacid.

18. A fibrous textile .article having adhered thereto a Water-repellent coating consisting essentially of an ester of a carboxyalkyl dextran in which the alkyl group containsfrom 1 to 5 carbon atoms with a saturated .fatty acid containing from 8 to 18 carbon atoms, said ester containing, per anhydroglucopyranosidic unit, an average of less than 1.0 to 1.5 carboxyalkyl groups and an average of less than 1.0 to 2.9 radicals derived from the .fatty acid.

19. A method for modifying the water-resistance of a fibrous textile article which comprises treating the textile with a liquid medium containing an ester of dextran,containing initially at least some free hydroxyl groups, with a saturated fatty acid containing from .8 to 18 carbon atoms, and drying the textile article to leave a coating of the ester adhered thereto.

20. A method for modifying the water-resistance of a fibrous textile article which comprises treating the textile with a liquid medium containing an ester of dextran'with a saturated fatty acid containing from 8 to 18 carbon atoms, and drying the textile article to leave a coating of the ester adhered thereto.

21. A method as in claim 19, characterized in that the dextran ester is dissolved in chloroform.

22. A method as in claim 19, characterized in that the dextran ester is dissolved in carbon tetrachloride.

23. A method for modifying the water-resistance of a fibrous textile article which comprises treating the textile with a liquid medium containing an ester of dextran, containing initially at least some free hydroxyl groups, with a saturated fatty acid containing from 8 to 18 carbon atoms, said ester containing, per anhydroglucopyranosidic unit of the dextran, an average of 2.5 to 3.0 radicals drived from the fatty acid, and drying the textile article to'leave a coating of the ester adhered thereto.

24. A method for rendering a fibrous textile article water-repellent which comprises treating the article with a halogenated hydrocarbon solution of dextran stearate containing, per anhydroglucopyranosidic unit, an average of 2.5 to 3.0 stearoyl groups, and drying the article to leave a coating of the dextran stearate adhered thereto.

Harrison: Paper Trade Journal, vol. 119, No. 5, 1944, pages 28 to 38. 

5. A FIBROUS TEXTILE ARTICLE HAVING ADHERED THERETO A PROTECTIVE WATER-RESISTANT COATING CONSISTING ESSENTIALLY OF AN ESTER OF DEXTRAN WITH A SATURATED FATTY ACID CONTAINING FROM 8 TO 18 CARBON ATOMS. 